Minimally invasive methods and devices for the treatment of prostate diseases

ABSTRACT

Methods and systems for resecting and debulking prostatic tissue to utilize a shaft carrying an energy source. The shaft is anchored by a balloon or other structure expanded in the bladder, and the energy source is capable of directing ablative energy radially outwardly from the urethra, where the energy source will be moved in order to remove a pre-defined volume of prostatic tissue.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of provisional application60/883,097, filed on Jan. 2, 2007, the full disclosure of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to medical methods and devices.In particular, the present invention relates to methods and devices forapplying energy to the urethra to achieve volumetric tissue reduction.

A number of medical conditions affect the male urethra causing a varietyof symptoms including painful or difficult urination, a swollenprostate, blood in the urine, lower back pain, and the like. Some ofthese conditions, such as prostatitis, are bacterial infections whichcan be treated with antibiotics and other drugs. Other conditions,however, such as benign prostatic hyperplasia (BPH) and prostaticcarcinoma, result in enlargement of the prostate and obstruction of theurethra, sometimes leading to complete loss of bladder function.

Both BPH and prostatic cancer require treatments which remove or shrinktissue in the prostate surrounding the urethra. Common treatmentsinclude transurethral resection of the prostate (TURP) where aresectoscope is placed in the urethra and used to remove excessprostatic tissue. Another procedure, referred to as transurethralincision of the prostate (TUIP), relies on cutting muscle adjacent tothe prostate to relax the bladder opening to relieve difficulty inurination. More recently, a procedure referred to as transurethralneedle ablation (TUNA) has been introduced where a needle is advancedthrough the urethra into the prostate and used to deliver energy, suchas microwave, radiofrequency, or ultrasound energy, to reduce the sizeof the prostate, again relieving pressure on the urethra. Laser ablationusing transurethral optical fibers also finds use.

While generally successful, none of these methods are adequate to treatall patients and all conditions. In particular, patients having severetissue intrusion into the urethral lumen resulting from BPH or prostaticcancer are difficult to treat with minimally invasive protocols whichrely on tissue shrinkage rather than resection. Thus, many of thesepatients will eventually require conventional surgical resection.

For these reasons, it would be desirable to provide minimally invasivemethods and devices which provide for enlarging the luminal area and/orvolumetric resection of tissue surrounding the urethra. It would beparticularly desirable if such methods and devices provided for removalor destruction of such tissues surrounding the urethra where the removalor destruction products can be removed from the lumen to relievepressure on the urethra, even where large volumes of tissue have beenremoved. Alternatively or additionally, the methods and devices shouldprovide for anchoring of the treatment device relative to the urethra inorder to provide a stable platform for treatment protocols which do notrequire visualization. Methods and devices for performing such protocolsshould present minimal risk to the patient, should be relatively easy toperform by the treating physician, and should allow for alleviation ofsymptoms with minimal complications even in patients with severedisease. At least some of these objectives will be met by the inventionsdescribed below.

2. Description of the Background Art

Use of a transurethral endoscope for bipolar radiofrequency prostatevaporization is described in Boffo et al. (2001) J. Endourol.15:313-316. Radiofrequency discharge in saline solutions to producetissue-ablative plasmas is discussed in Woloszko et al. (2002) IEEETrans. Plasma Sci. 30:1376-1383 and Stalder et al. (2001) Appl. Phys.Lett. 79:4503-4505. Air/water jets for resecting tissue are described inJian and Jiajun (2001) Trans. ASME 246-248. US2005/0288639 described aneedle injector on a catheter based system which can be anchored in aurethra by a balloon in the bladder. U.S. Pat. Nos. 6,890,332;6,821,275; and 6,413,256 each describe catheters for producing an RFplasma for tissue ablation. Other patents and published applications ofinterest include: U.S. Pat. Nos. 7,015,253; 6,890,332; 6,821,275;6,413,256; 6,378,525; 6,296,639; 6,231,591; 6,217,860; 6,200,573;6,179,831; 6,142,991; 6,022,860; 5,994,362; 5,872,150; 5,861,002;5,817,649; 5,770,603; 5,753,641; 5,672,171; 5,630,794; 5,562,703;5,322,503; 5,116,615; 4,760,071; 4,636,505; 4,461,283; 4,386,080;4,377,584; 4,239,776; 4,220,735; 4,097,578; 3,875,229; 3,847,988;US2002/0040220; US2001/0048942; WO 93/15664; and WO 92/10142.

BRIEF SUMMARY OF THE INVENTION

Methods, devices, and systems according to the present invention providefor intraluminal delivery of energy, to ablate or resect tissuesurrounding a urethra. The present invention is particularly intendedfor treating benign prostatic hyperplasia (BPH) and prostatic carcinoma,both of which can result in compression and partial or total occlusionof the urethra. Treatments comprise positioning an energy source withinthe urethra and directing energy radially outwardly from the energysource toward the urethral wall within the prostate. The energy sourcewill usually be moved relative to the urethra to remove a pre-definedvolume of prostate tissue surrounding the urethral lumen in order topartially or fully relieve the compression and/or obstruction. In otherembodiments, however, the therapy may comprise mechanical, thermal,acoustic or vibrational, cryotherapy or other forms of treatment for BPHand other conditions. Optionally, the treatments of the presentinvention may be combined with chemotherapy and other forms of drugdelivery, as well as treatment with external X-ray and other radiationsources and administration of radiopharmaceuticals comprisingtherapeutic radioisotopes. For example, one or more drugs may becombined with the saline or other fluid which is used for energydelivery. The combination liquid/gas delivery can be used to both resecttissue and wash the tissue away while leaving intra-prostatic bloodvessels, capsule, and sphincter muscle undamaged. Thus, benefits of thehigh pressure liquid/gas energy source include limited bleeding withreduced or no need for cauterization and decreased risk of perforatingor otherwise damaging the capsule of sphincter muscles. Alternatively,the device which is used to position the energy source can be utilizedto separately deliver a desired chemotherapeutic or other drug (as justset forth), either before, during, or after energy treatment accordingto the present invention. While the present invention is specificallydirected at transurethral treatment of the prostate, certain aspects ofthe invention may also find use in the treatment of other body lumens,organs, passages, tissues, and the like, such as the ureter, colon,esophagus, lung passages, bone marrow, and blood vessels.

Thus, in a first aspect of the present invention, methods for resectingand removing prostate tissue comprise positioning an energy sourcewithin the urethra and directing energy radially outwardly from theenergy source toward a wall of the urethra within the prostate. Theenergy source is then moved relative to the urethra to remove apre-defined volume of tissue surrounding the lumen. In a particularaspect of the present invention, the method further comprises expandingan anchor within the bladder at the distal end of the urethra. Theenergy source is then positioned and moved relative to the anchor toassure that the treatment is properly directed to prostatic tissue. Theuse of the anchor is particularly advantageous since it allows theprocedures to be performed without endoscopic, fluoroscopic, or otherimaging. The methods of the present invention, of course, do not excludesuch imaging, but rather permit the methods to be performed when desiredwithout further imaging.

Usually, the energy source and the anchor will be mounted on a commoncatheter assembly, more typically on a single shaft. Thus, the catheterassembly or shaft may be maintained in a fixed or immobilized positionwithin the urethra by either applying a tension which engages the anchoragainst the bladder wall, or preferably by expanding the anchor fullywithin the bladder to reduce the risk that the catheter assembly orshaft can be accidentally dislodged.

The energy source can be any one or a combination of variousconventional energy sources which can be used to resect or ablatetissues. A first exemplary energy source comprises high pressure fluids,such as water, saline, liquid therapeutic agent, or the like. The highpressure fluid is often a combination of a liquid and gas, such as waterand air, and can be delivered radially outwardly in one or more fluidstreams which impinge directly against the urethral wall and prostatictissue to resect or debulk the tissue. The fluid stream(s) may bedirected at a generally perpendicular or normal angle relative to acatheter assembly or shaft, and may also be directed at other angle(s),typically in the range from 10° to 90°, more typically from 45° to 90°,relative to the shaft or catheter assembly which carries the port orejector used to deliver the fluid(s) including, for example,anesthetics, antibiotics, anti-inflammatories, anti-neoplastics,tissue-specific growth factors, anti-growth factors, hormones,anti-hormones, vasodilators, vitamins, proteins, and the like.

The energy source may also deliver laser energy used to ablate tissue.The laser energy will usually be delivered by an optical waveguide orfiber bundle carried within a catheter assembly or shaft which isintroduced through the urethra. The laser energy can then be directedradially outwardly either by deflecting the shaft and/or by using amirror to reflect the energy. The mirror may optionally have a surfacewhich focuses or defocuses the energy in a desired manner as it isdelivered to the prostatic tissue.

A third suitable energy source comprises an electrically conductivefluid which carries radiofrequency current, optionally generating aplasma of the conductive fluid. One or more streams of such electricallyconductive fluids may be directed outwardly through ceramic nozzles orother distribution elements.

A fourth energy source comprises an electrode adapted to deliverradiofrequency energy. The electrode will have a deflected ordeflectable distal end which can be directed radially outwardly from acatheter assembly or shaft which carries the electrode into the urethra.The tip or other surface of the electrode can thus be engaged againstthe urethral wall and prostatic tissue in order to deliver ablativeradiofrequency energy into the tissue.

The methods of the present invention may further comprise associatedsteps and processes to assist in the tissue resection and ablation. Inorder to gain a working space within the urethra, the methods mayfurther comprise introducing a pressurized gas to expand (insufflate)the urethra lumen prior to or while directing the energy radiallyoutwardly into the prostatic tissue. Further optionally, the ablation orresection products may be aspirated from the urethra, typically througha lumen in the catheter assembly or shaft used to deliver the energysource. In combination with aspiration, the urethra may also be flushedwith saline or other fluid to assist in removing the ablation orresection products. Usually, both flushing and aspiration will beperformed using lumens in the same catheter assembly or shaft which hasbeen used to position the energy source.

The energy source will be moved in a pre-defined manner relative to theanchored shaft or urethra in order to selectively treat the prostatictissue. Typically, the energy source will be moved to cover and treat acylindrical volume of prostatic tissue surrounding the urethra. In suchcases, the energy source will typically be rotated and/or axiallytranslated within the urethra so that the energy is uniformly deliveredinto the urethral wall. Alternatively, the energy source may be scannedto a non-cylindrical and optionally non-symmetric region within theurethra which has been targeted for treatment. Various combinations ofrotation, axial translation, rotational oscillation, and axialoscillation may be used.

In a separate aspect of the present invention, methods for treating aprostate comprise advancing a shaft through a urethra. An anchor on theshaft is expanded in a bladder to stabilize the shaft in the urethra,that is to fix the position relative to the urethral wall. The treatmentdevice on the shaft is then activated to enlarge the urethra and/ordebulk the prostate, where the position of the treatment device is fixedby the anchor. Usually, the anchor comprises a balloon which is inflatedwithin the bladder, typically being inflated to fully occupy the entirevolume of the urethra so that the risk of dislodgement is reduced.Actuating the treatment device may comprise use of any one of the energysources described above, broadly including applying mechanical,vibrational, thermal, optical, and/or electrical energy to the prostatictissue from the stabilized shaft. Usually, the treatment device will bemoved relative to the shaft to treat a pre-defined surface region of theurethra, where the pre-defined surface region is usually cylindrical butmay be non-cylindrical and non-symmetric as also described above.Typically, the treatment device emits a stream or circumferential bandof energy, where movement comprises at least axial translation and/oraxial oscillation. Usually, movement will further comprise rotationand/or rotational oscillation.

In addition to the methods described above, the present invention alsoprovides prostate resection devices comprising a shaft, an expandableanchor, and at least one energy source. The shaft has a proximal end anda distal end. The expandable anchor is positioned on the shaft near itsdistal end and is adapted for anchoring within the bladder. The at leastone energy source is also on the shaft and is spaced proximally of theanchor by a distance selected to position the energy source within adesired region of the urethra, typically within the prostate, when theanchor is positioned in the bladder. Thus, the energy may be deliveredradially outwardly from the energy source selectively into the targetprostate tissue without the need for imaging or other positioningmethods or apparatus.

The prostate resection devices of the present invention may furthercomprise various lumens in the shaft for performing supplementalportions of the procedure. For example, the shaft may comprise one ormore lumens for delivering a gas or fluid to pressurize and enlarge(insufflate) the urethra surrounding the energy source. One or moreadditional lumens may be provided for aspirating the urethra to removeablation products and/or for delivering fluids to flush the urethra toremove ablation or resection products. The shaft will be adapted fordelivery in a retrograde direction into the male urethra, typicallyhaving a width in the range from 1 mm to 10 mm and a length in the rangefrom 15 cm to 25 cm.

The prostate resection devices of the present invention may comprise anyof the various energy sources described above. Usually, the energysource will be movable relative to the shaft to allow for selectivelydirecting energy at different regions of the prostate. More typically,the energy source may be translated, rotated, translationallyoscillated, and/or rotationally oscillated relative to the shaft.Exemplary energy sources comprise a high pressure fluid ejector, such asa nozzle or other port connected to additional lumen(s) in the shaft, alaser energy source, such as an optical fiber optionally combined with amirror for reflecting the laser energy, a conductive fluid source incombination with a radiofrequency energy source, and/or an electrodethat can be positioned against the urethral wall to deliverradiofrequency energy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a device suitable for performingintraurethral prostatic tissue debulking in accordance with theprinciples of the present invention.

FIGS. 2A-2D illustrate use of the device of FIG. 1 in performingprostatic tissue debulking.

FIG. 3 illustrates a specific prostatic tissue treatment deviceincorporating the use of a radiofrequency saline plasma for performingprostatic tissue debulking.

FIG. 4 illustrates an energy source suitable for use in the devices ofthe present invention, wherein the energy source delivers a highpressure fluid for tissue resection.

FIG. 5 illustrates an energy source suitable for use in devices of thepresent invention, wherein the energy source comprises a deflectedoptical waveguide for delivering laser energy to the prostatic tissue.

FIG. 6 illustrates a device similar to that shown in FIG. 5, except theoptical waveguide directs laser energy at a mirror which laterallydeflects the laser energy.

FIG. 7 illustrates an energy source suitable for use in the devices ofthe present invention, wherein the energy source comprises a laterallyprojecting electrode which can engage the urethral wall and prostatictissue to deliver radiofrequency energy for tissue ablation.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, an exemplary prostatic tissue debulking device 10constructed in accordance with the principles of the present inventioncomprises a catheter assembly generally including a shaft 12 having adistal end 14 and a proximal end 16. The shaft 12 will typically be apolymeric extrusion including one, two, three, four, or more axiallumens extending from a hub 18 at the proximal end 16 to locations nearthe distal end 14. The shaft 12 will generally have a length in therange from 15 cm to 25 cm and a diameter in the range from 1 mm to 10mm, usually from 2 mm to 6 mm. The shaft will have sufficient columnstrength so that it may be introduced upwardly through the male urethra,as described in more detail below.

The shaft will include an energy source positioned in the energydelivery region 20, where the energy source can be any one of a numberof specific components as discussed in more detail below. Distal to theenergy delivery region, an inflatable anchoring balloon 24 will bepositioned at or very close to the distal end 14 of the shaft. Theballoon will be connected through one of the axial lumens to a ballooninflation source 26 connected through the hub 18. In addition to theenergy source 22 and the balloon inflation source 26, the hub willoptionally further include connections for an infusion/flushing source28, an aspiration (a vacuum) source 30, and/or an insufflation(pressurized CO₂ or other gas) source 32. In the exemplary embodiment,the infusion or flushing source 28 can be connected through an axiallumen (not shown) to one or more delivery ports 34 proximal to theballoon anchor 24 and distal to the energy delivery region 20. Theaspiration source 30 can be connected to a second port or opening 36,usually positioned proximally of the energy delivery region 20, whilethe insufflation source 32 can be connected to an additional port 38,also usually located proximal of the energy delivery region. It will beappreciated that the locations of the ports 34, 36, and 38 are notcritical, and that the lumens and delivery means could be provided byadditional catheters, tubes, and the like, for example including coaxialsleeves, sheathes, and the like which could be positioned over the shaft12.

Referring now to FIGS. 2A-2D, the prostatic tissue debulking device 10is introduced through the male urethra U to a region within the prostateP which is located immediately distal to the bladder B. The anatomy isshown in FIG. 2A. Once the catheter 10 has been positioned so that theanchoring balloon 24 is located just distal of the bladder neck BN (FIG.2B) the balloon can be inflated, preferably to occupy substantially theentire interior of the bladder, as shown in FIG. 2C. Once the anchoringballoon 24 is inflated, the position of the prostatic tissue debulkingdevice 10 will be fixed and stabilized within the urethra U so that theenergy delivery region 20 is positioned within the prostate P. It willbe appreciated that proper positioning of the energy delivery region 20depends only on the inflation of the anchoring balloon 24 within thebladder. As the prostate is located immediately proximal to the bladderneck BN and by spacing the distal end of the energy delivery region veryclose to the proximal end of the balloon, the delivery region can beproperly located, typically having a length in the range from 0 mm to 5mm, preferably from 1 mm to 3 mm. After the anchoring balloon 24 hasbeen inflated, energy can be delivered into the prostate for debulking,as shown by the arrows in FIG. 2. Once the energy has been delivered fora time and over a desired surface region, the energy region can bestopped and the prostate will be debulked to relieve pressure on theurethra, as shown in FIG. 2D. At that time, a flushing fluid may bedelivered through port 34 and aspirated into port 36, as shown in FIG.2D. Optionally, after the treatment, the area could be cauterized usinga cauterizing balloon and/or stent which could be placed using aseparate catheter device.

Referring now to FIGS. 3-7, a number of representative energy deliveryregions will be described. Referring now to FIG. 3, a first exemplaryprostate resection device 110 constructed in accordance with theprinciples of the present invention comprises a shaft 112 having aproximal end 114 and a distal end 116. A plurality of nozzles 118 aremounted on the shaft 112 at a location spaced proximally from the distalend 116 by distance in the range from 1 cm to 5 cm. The nozzles, whichare typically ceramic cores capable of generating a plasma or portscapable of directing a radially outward stream of electricallyconductive fluid, may be mounted on structure 120, which allows thenozzles 118 to be moved radially outwardly, as shown in broken line inFIG. 3. An anchor 122, shown as an inflatable balloon is mounted on thedistal end 116 of the shaft 112 at a location between the nozzles 118and the distal tip 124. The expandable structure 122 will be capable ofbeing expanded within the bladder to anchor the shaft 112 so that thenozzle array 118 lies within the prostate, as described in more detailbelow. The shaft 112 will include lumens, passages, electricallyconductive wires, and the like, in order to deliver energy and materialsfrom the proximal end 114 to the distal end 116 of the shaft. Forexample, an RF energy source 126 will be connected to the shaft 112,usually to the nozzles 118, in order to deliver RF energy to anelectrically conductive fluid delivered from source 128 to the nozzles118, typically through a lumen within the shaft 112. Other lumens,channels, or conduits will be provided in order to allow aspiration to avacuum source 130 which is typically connected to one or more aspirationports 132. Other conduits may be provided within the shaft 112 in orderto permit introduction of a flushing fluid, such as saline, from asource 134 to ports 136. In other instances, it will be possible toconnect the aspiration and flushing sources 130 and 134 to a common portso that aspiration and flushing may be conducted sequentially ratherthan simultaneously. Further optionally, internal lumens, conduits, orthe like, may be provided in order to connect a source of insufflation140 to one or more insufflation ports 142 on the shaft in the region ofthe array 118. Finally, internal lumens, conduits, or the like, may beprovided for connecting balloon 122 to a balloon inflation source 144.

As shown in FIG. 4, an exemplary energy delivery region 20 can be formedby a high pressure nozzle 200 which is carried on a delivery tube 202which is disposed within the shaft 12. Carrier tube 202 may be axiallytranslated as shown by arrow 204 and/or rotated as shown by arrow 206 sothat the high pressure stream 208 emanating from the nozzle 200 can bescanned or rastered over all or a selected portion of the urethra withinthe prostate. Specific pressures and other details for such highpressure water treatment are described, for example, in Jian and Jiajun,supra.

Referring now to FIG. 5, the energy source within the energy deliveryregion 20 may comprise a fiberoptic waveguide or fiber bundle 220carried on the rotating and translating shaft 202. The optical waveguide220 transmits laser or other coherent optical energy in a beam 222 whichmay be scanned or rastered over the urethral wall and prostatic tissueby rotating and/or translating the carrier tube 202.

As shown in FIG. 6, laser energy from an optical waveguide or fiberbundle 230 may be directed axially against a mirror 232, where thewaveguide and mirror are both carried on the rotating and axiallytranslating carrier tube 202. Again, by rotating and/or translating thecarrier tube 202, the emanating beam 234 can be scanned or rastered overthe urethral wall.

Referring now to FIG. 7, in yet another embodiment, the rotating andaxially translating tube 202 may carry an electrode 240 which projectslaterally from the tube. The electrode 240 will be adapted forconnection to a radiofrequency energy source so that, when the electrodecontacts the urethral wall and prostatic tissue, radiofrequency energycan be delivered, either in a monopolar or bipolar mode. Theradiofrequency energy can thus ablate the tissue over selected volumesand regions of the prostatic tissue. Optionally, by changing the natureof the radiofrequency energy, the electrode 240 could also be used tocauterize the tissue after it has been treated.

While the above is a complete description of the preferred embodimentsof the invention, various alternatives, modifications, and equivalentsmay be used. Therefore, the above description should not be taken aslimiting the scope of the invention which is defined by the appendedclaims.

1. A method for prostate tissue resection, said method comprising:positioning a catheter assembly having a shaft which carries an energysource within a lumen of a urethra; directing a high pressure liquidstream radially outwardly from the energy source toward a wall of theurethra within the prostate; and moving the shaft within the catheterassembly to axially oscillate the energy source relative to the urethra,wherein the liquid stream mechanically resects a pre-defined volume oftissue surrounding the lumen, wherein the position of the catheterassembly remains positioned in the urethra while the energy source isaxially oscillated relative to the shaft.
 2. A method as in claim 1,wherein the liquid stream comprises an electrically conductive fluid,further comprising providing a radiofrequency current source anddelivering radiofrequency current from said source to said liquidstream.
 3. A method as in claim 1, further comprising introducing apressurized gas to expand the urethra while the high pressure liquidstream is directed radially outwardly.
 4. A method as in claim 1,further comprising aspirating the urethra to remove ablation products.5. A method as in claim 4, further comprising flushing the urethra tohelp remove ablation products.
 6. A method as in claim 5, whereinaspirating and flushing are performed with a device which also carriesthe energy source.
 7. A method as in claim 1, wherein moving comprises acombination of rotation and axial translation.
 8. A method as in claim7, wherein rotation comprises rotational oscillation.
 9. A method fordebulking a prostate, said method comprising: axially oscillating androtating a shaft within a catheter assembly disposed in a lumen of aurethra; stabilizing the catheter assembly in the urethra as the shaftis being axially oscillated; and directing a high pressure liquid streamradially outwardly from the shaft to mechanically resect tissuesurrounding the urethra to debulk the prostate.
 10. A method as in claim9, wherein the high pressure liquid stream comprises a liquid and gas.11. A method as in claim 9, wherein the shaft is axially oscillated totreat a predefined surface region of the urethra.
 12. A method as inclaim 11, wherein the predefined surface region is generallycylindrical.